urs scott wilson associate director [email protected] daru widyatmoko pavement...
TRANSCRIPT
• URS Scott Wilson
• Associate Director
Daru Widyatmoko
PAVEMENT SUSTAINABILITY AND PERFORMANCE IMPROVEMENT:
CASE STUDIES
Co-Authors
URS Scott Wilson
Technical Director
Bachar Hakim
Colas Ltd
Operations Director
Carl Fergusson
Introduction
• From Grooved Marshall Asphalt to Ungrooved Airfield Asphalt Concrete
• Progress to date – case studies• Friction characteristics• Sustainable pavement solutions• Benefits• Conclusions
Reasons for using improved materials
• Pressure to maximise runway availability• Low maintenance• Better whole life cost• Sustainability• Requirements to demonstrate best value
UK airfield asphalt materials
• Grooved Marshall Asphalt surfacing• Marshall Asphalt binder course• Dense Macadam binder course/base
French airfield asphalts• Ungrooved Airfield Asphalt Surfacings
– BBA (Bétons Bitumineux pour chausées Aeronautiques) surface/binder course
• High Modulus Asphalts– BBME (Bétons Bitumineux à Module Elévé)
surface course, – EME (Enrobé à Module Elévé) binder
course/base
BBA classification• Four types
Type Average Thickness (mm) Minimum thickness at any point (mm)
Continuously graded – 0/10(AC 10-BBA C) 60 - 70 40
Continuously graded – 0/14(AC 14-BBA C) 70 – 90 50
Gap-graded 0/10(AC 10-BBA D) 40 – 50 30
Gap-graded 0/14(AC 14-BBA D) 50 - 70 40
• Three classes: 1, 2 and 3 depending upon the Performance Levels
French Airfield Materials• BBA surface and binder course• French National Standards• Track records > 25 years• Performance based designfor surface and binder or base
courses that will be subjected to high traffic of heavy aircraft and includes a verification of the resistance to rutting with the wheel-tracking rut tester
mandatory in every case
applies to base, binder and surface course mixes when the determination of the stiffness of the mix is required for pavement design purposes
carried out for heavily trafficked pavements, for mixes used in base layers of new pavements or of overlays in relation to pavement design
recipe mix for non-traffic area only
Source: LPC Bituminous Mixtures Design Guide
BBA vs MA Surfacing
BBA has better stiffness, fatigue, deformation, durability and stability to receive grooving than MA
0.5 1.0 1.5 2.0 2.5 3.0
Performance Ratio between the AC10-BBA over AC14-MA
Stiffness
DeformationResistance
Fatigue Resistance
Resistance toMoisture Damage
Reduced thickness
Lower risk of rutting (t/w)
Better crack resistance
Durable
Grooved “BBA”
• All surfaced with grooved 0/10mm BBA (AC 10-BBA)
• The use of 0/14mm BBA (AC 10-BBA) as enhanced binder course
• Use of local and RAP materials
Ungrooved BBA
• July 2011: ungrooved 0/14mm BBA (AC 14-BBA D) surface course at Manchester International Airport
• March 2011: ungrooved 0/14mm BBA (AC 14-BBA D) surface course and binder course at London Southend Airport
Class and type of BBA materialsMaterial ID MAT-01 MAT-02 MAT-03 MAT-04 MAT-05
Mix AC10-BBA D AC10-BBA D AC10-BBA C AC14-BBA D AC10-BBA C
Nominal Aggregate Size
0/10mm 0/10mm 0/10mm 0/14mm 0/10mm
Type of Grading Discontinuous Discontinuous Continuous Discontinuous Continuous
Layer Surface Course Surface Course Surface Course Binder Course Surface Course
Binder Pen 40/60+ Pen 40/60+ Colflex N Pen 35/50+ Colflex N
Class 3 3 3 2 2
Design Level 3 2 3 3 3
Coarse Aggregate PSV
66 58 55 – 60 48 60
Fine Aggregate PSV (parent rock)
66 65 55 – 60 53 48
Surface Characteristics• Texture depth
– Minimum average texture depth of 1mm (ICAO and CAP168 of CAA)
– Minimum texture depth of 0.6mm on runways for 90% of the zones tested (AFNOR, 1999)
• Wet friction characteristics – Using Continuous Friction Measurement Equipment (CFME), such
as Mu-Meter, Grip Tester and IMAG.
Continuous Friction
Measuring Equipment
Minimum Design Objective Level
(DOL)
Maintenance Planning Level
(MPL)Minimum Friction
Level (MFL)
CAA ICAO CAA ICAO CAA ICAO
Mu-meter 0.72 0.72 0.57 0.52 0.50 0.42
Grip Tester 0.80 0.74 0.63 0.53 0.55 0.43Note: CAA specifies water depth of 0.5mm and 0.25mm for the wet friction assessment using Mu-meter and Grip Tester respectively, whilst ICAO specifies water depth of 1mm for these tests.
European Friction Measurement
• Skid resistance – ICAO Annex 14, Vol1, Supplement A, Chapter7
Measuring apparatus Speed of test in km/h Nominal level for new runway surfaces
Skidometre BV 11 65 0.8295 0.74
IMAG 65 0.5395 0.44
ADHERA 65 0.4595 0.34
TTURL [CAP 781]
Classification • According to JAR OPS 1, paved runways which have been specially prepared
with grooves or porous pavement may be considered as having “effectively dry” braking action even when moisture is present, but provided that it is not contaminated (i.e. no WATER PATCHES or FLOODED).
But:
• How Many Grooves?
• What Size?
• What Spacing?
Early Life Surface characteristicsMaterial ID MAT-01 MAT-02 MAT-03 MAT-04 MAT-05
Mix AC10-BBA D AC10-BBA D AC10-BBA C AC14-BBA D AC10-BBA C
Layer Surface Course Surface Course Surface Course Binder Course Surface Course
Mean Texture Depth as Laid
0.8mm 0.6mm 0.5mm 1.0mm 0.5mm
Mean Texture depth after grooving
1.0mm 1.0mm 0.9mm *see Note 1.0mm
Groove Dimension (mm x mm x mm)
4x4x25 4x4x25 3x3x25 *see Note 4x4x25
Continuous Friction Measurement Equipment
Mu-meter at 0.5mm water depth Grip Tester at 0.25mm water depth
Average friction results prior to grooving
Not available 0.63 0.68 0.73 0.72
Average friction results after grooving
0.63 0.66 0.69 *see Note 0.72
CAA CAP 683 Requirements
MFL = 0.50,MPL = 0.57,DOL > 0.72
MFL = 0.55,MPL = 0.63,DOL > 0.80
Ungrooved Asphalt Early Life
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
AC14-BBA D [MAT-04]Ungrooved; MTD = 1.0mm
AC10-BBA C [MAT-05] BeforeGrooving; MTD = 0.5mm
AC14-MA [MAT-06] BeforeGrooving; MTD = 0.3mm
Fri
ctio
n V
alu
e (G
rip
Tes
ter
at 6
5 km
/h) mean value
minimum value
MFL
MPL
BBA BBA MA
Maintenance Planning Level
Minimum Friction Level
Ungrooved and Grooved Asphalts Early Life
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
AC14-BBA D [MAT-04]Ungrooved; MTD = 1.0mm
AC10-BBA C [MAT-05] AfterGrooving; MTD = 1.0mm
AC14-MA [MAT-06] AfterGrooving; MTD = 1.1mm
Fri
ctio
n V
alu
e (G
rip
Tes
ter
at 6
5 km
/h)
mean valueminimum value
MFL
MPL
BBA BBA MA
Maintenance Planning Level
Minimum Friction Level
Groove Retention
Changes in Friction Value with time
0.66
0.66
0.63
0.66
0.81
0.66
0.74
0.77
0.83 0.
85
0.74
0.4
0.5
0.6
0.7
0.8
0.9
1 6 14 20 180 14 122 180 440 810 1200
Days after Laying
Fri
cti
on
Va
lue
(M
u-m
ete
r a
t 6
5 k
m/h
)
Before Grooving After Grooving
MAT-02 MAT-01
MFL
MPL
DOL
Changes in Friction Value with time, measured by Mu-Meter at water depth of 0.5mm, for MAT-01 and MAT-02 surfacings
Changes in Friction Value with time
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
-20 -15 -10 -5 0 5 10 15 20
Distance from Centre Line (m)(The minus sign denotes the distance to left side of the runway centre)
GT
Fri
cti
on
Va
lue
Day 770,Winter
Day 592,Summer
Day 441,Winter
Day 326,Winter
Day 201,Summer
Day 94,Winter
Day 1,Winter
DOL = 0.80
MPL = 0.63
MFL = 0.55
Changes in Friction Value with time, measured by Grip Tester, at 0.25mm water depth, MAT-05 surfacing
Sustainable Pavement Solutions
• Hot Ex Situ Recycling incorporating Reclaimed Asphalt Pavement (RAP)– RAP incorporated in BBA binder course and
surface course at Jersey Airport• Repave Hot In Situ Recycling
– Repave process on taxiways at Isle of Man Airport• Full Depth Cold In Situ Recycling
– Deep recycling options adopted at Isle of Man Airport taxiways
Options and Actual TreatmentsTaxiway Conventional Design Recycling Design Actual Treatment Performed on
Taxiway
Bravo South No structural treatment required. Repave 30mm BBA.
Charlie South Remove 160mm existing pavement materials and replace with 50mm surface course on 110mm HDM binder/base.
Remove 365mm existing pavement materials and replace with 100mm surfacing on 265mm cold recycled H1 HBM material.
Remove 365mm existing pavement materials and replace with 100mm surfacing (comprising 40mm BBA surface course on 60mm HDM binder course) on 265mm cold recycled H1 HBM material.
Delta East
Delta West
Echo East Overlay with 40mm BBA surface course after repairing cracks and defects.
N/A Repave 30mm BBA.
Echo West
Foxtrot North No structural treatment required. Overlay 45mm BBA.
Foxtrot South Remove 160mm existing pavement materials and replace with 50mm surface course on 110mm HDM binder/base.
Remove 350mm existing pavement materials and replace with 100mm surfacing on 250mm cold recycled H1 HBM material.
Remove 365mm existing pavement materials and replace with 100mm surfacing (comprising 40mm BBA surface course on 60mm HDM binder course) on 265mm cold recycled H1 HBM material.
Benefits from Sustainable Pavement
• Substantial saving in cost (40%); • Energy consumption (44%), and; • Carbon dioxide emissions (32%).
Hakim, B. and Fergusson, C. Sustainable Pavement Construction at the Isle of Man Airport. Asphalt Professional No. 46, November 2010
Conclusions (1)• Use of BBA for binder course when runways are in
temporary condition is advantageous;
• Greater length of Temporary Total Ungrooved Runway Length (TTURL) can be considered when BBA is used;
• Rapid achievement of Design Objective Level (DOL) friction;
Conclusions (2)• BBA groove stability is not an issue;• A good comparison can be made between the
ungrooved AC 14-BBA D, grooved AC 10-BBA, and grooved AC 14-MA in terms of friction;
• AC 14-BBA D have now been used in surface course;
• Sustainable pavement solutions can be incorporated and were regarded cost effective
Thank You